They Eat Viruses

Scientists don’t often get to make major new discoveries, but maybe for the first time, they’ve found organisms that dine on viruses. And that would make sense because viruses are EVERYWHERE and their biomass is several times that of all humans on earth. So, organisms that can actually feed on viruses would have an ideal food source. To find these organisms, scientists placed water collected from the Gulf of Maine and the Mediterranean into a flow cytometer. It sorts cells floating in water based on their physical features. There were seventeen-hundred planktonic protists, which are single cell eukaryotes.

When scientists analyzed their DNA, about half from the Mediterranean and a fifth from the Gulf of Maine contain bacterial DNA which makes sense since they eat bacteria.

But about the same amount also had pieces of viral DNA from up to fifty different viruses. Most were types of bacteriophages which are viruses that infect bacteria.

What really made scientists believe these organisms ate viruses were two particular protists: picozoans and choanozoans. Neither had ANY bacterial DNA but they all had similar types of bacteriophage DNA even though these two protists are not closely related. So, most likely they did not pick up the viruses by chance!

We don’t know how this affects the ocean’s food chain, however, since viruses contain phosphorous and nitrogen, imagine finding out that life on Earth depends on this cycle!